1. Field of the Invention
The present invention generally relates to a recording control system and more particularly relates to a recording control system capable of preventing dubbing operation or undesirable copy of recorded information.
2. Description of the Prior Art
In recent years, due to the spread of video tape recorders and audio tape recorders etc., illegal reproductions of video software or audio software etc. have appeared on the market as pirated editions or versions, so that the protection of the copyright of these software has been strongly demanded.
Thus, as a system for preventing the illegal-dubbing operation, such a system as a copy guard system utilizing the nature of the video signal etc. has been applied to the video software on the market. This copy guard system operates in a manner that, if an illegal dubbing operation is performed for video software or undesirable copying operation, noise data as well as the video software data are recorded onto a tape mounted on a recording unit side to thereby degrade the reproduced image of the video software in case of reproducing the tape where the video software is copied thereon together with the noise signal.
However, in the conventional illegal-dubbing preventing system, the noise signal is merely superimposed on the data of the video software in order to prevent the illegal dubbing operation, so that the noise signal can be easily removed from the reproduced data to thereby obtain a sure copy of the video software by connecting a device for removing the noise signal in the transmitting line between a reproducing unit and a recording unit and then the recording unit records the data from which the noise signal is removed by the device. Thus, the conventional illegal-dubbing preventing system can not perform the dubbing preventing operation sufficiently. Further, such a device for invalidating the illegal-dubbing preventing function of the conventional illegal-dubbing preventing system has already been on the market. Accordingly, it is required to provide an illegal-dubbing or undesirable copy preventing system whose illegal-dubbing or undesirable copy preventing function is difficult to be invalidated.